This document is made available electronically by the Minnesota Legislative Reference Library as part of an ongoing digital archiving project. http://www.leg.state.mn.us/lrl/lrl.asp The 1979 Resource Inventory for Helen Allison Savanna Anoka County, Minnesota N~ of NE~ of Section 2, Township 33 North, Range 23 West Isanti Quadrangle Prepared by The Scientific and Natural Areas Section Division of Parks and Recreation Minnesota Department of Natural Resources December 1979 Draft TABLE OF CONTENTS Page INTRODUCTION Scope and Organization .•••. 0 0 • 1 2 Description of Study Area ••••• 0 • ,. Preliminary Assessment of Significance • 3 ABIOTIC FACTORS Climate • 0" • 6 Geology • 10 Soils · 15 Hydrology • 20 VEGETATIONAL COMPONENTS Vegetative Communities . 23 30 Flora • • 0 0 ZOOLOGICAL COMPONENTS 41 Birds 0 •• 0 • 47 Mammals .. 0 •• o • • • 49 Amphibians and Reptiles LAND USE HISTORY ••••••••••••• 0 •• 0 •••••••••• 52 .Support for th£s project was provided by Minnesota's Legislative 'Commission on Minnesota Resources. INTRODUCTION Scope and Organization This report documents the information collected during a 1979 inventory of Allison Savanna. The inventory recorded information on climate, geology, soils, hydrology, plant communities, flora, birds, mammals, amphibians, reptiles, and land use history of the natural area. Data supplied by this document will be used by the Minnesota Natural Her~tage Progtam and other evaluators to assess the site as a potential Scientific and Natural Area (SNA). The document can also be used by scientists, educators, and others interested in the area. Should the site De designated an SNA, management plans can be written using this docu~ent as, a reference. TlUs, report ;is divided ;Lnto five sections including: introduction, aoiotic, vegetational, and zoological components, and land use history of the site. Methodologies and results are presented for each section. The inventory of Allison Savanna was part of a larger 1979 effort ~n watch. eighteen natural areas in east central, northwest, and southeast ~nnesota were surveyed. Inventory team members were: John Borowske, SNA Planning Coordinator; Cherry Keller, Karen Lustig, Deb Schowalter, and Jeff Weigel, Researcher/Writers; Kathy Bolin, Community Specialist; and Nancy Berlin, Tony Busche, Barbara Eikum, Peter Farrell, Joanne Herman, Laura Hill, Susan Ottoson, Deanna Schmidt, Marianne Severson, Angela Tornes, and James Ziegler, Researchers. Gerald Jensen, Coordinator, 2 Scientific and Natural Areas Program, and Mark Heitlinger, Coordinator of Preserve Management, The Nature Conservancy, Minnesota Chapter served as inventory advisors. Michael Rees, Proje~t Editor, The Nature Conservancy, provided editorial assistance. Other individuals who assisted in the preparation of the inventory are mentioned in the appropriate sections. Their help is gratefully acknowledged • . Description of Study Area Helen Allison Savanna is an 86 acre unit in northeastern Anoka County, approximately 14 miles southeast of Cambridge, Minnesota. The area's climate is mid-continental, relatively cool and moist, with warm summers and cold winters. The tract is part of a larger glacial outwash area called the Anoka Sand Plain. Wind formed sand dunes and wet, poorly drained depressions are found on Allison Savanna. Generally poor drainage in low areas and a high water table contribute to wet conditions on the site, although higher dune areas are well drained. Sandy textured, easily erodable soils formed under a variety of vegetation types on the natural area. Present vegetation is primarily oak savanna with scattered sand dune blowouts and wet meadow. About 20 acres were formerly cultivated and now support old field vegetation. The flora and fauna of Allison Savanna are mostly typical of native M1nnesota grassland and savanna communities. Species observed on the tract include: 212 vascular plants, 45 birds, 11 mammals, 4 amphibians, and I reptile. Allison Savanna lies within a corn, soybean, oats, hay, and pasture 3 farming area, although wetness prevents extensive cultivation. Many residential developments are also in the area. The natural area has been lightly grazed; other impacts include field roads, and homesteading on the site. Preliminary Assessment of Significance This section lists features identified by the Minnesota Natural Heritage Program OMNHP) as potential elementsl , and identifies other aspects of the preserve believed by the authors to be important components of Minnesota's natural diversity, or which otherwise might qualify the site for SNA designation. Criteria for SNA evaluation are enumerated in '~nnesota Department of Natural Resources Policy Plan for Scientific and Natural Areas", dated July 6, 1979. Helen Allison Savanna is notable as a tract of native vegetation on the Anoka Sandplain glacial outwash deposit. Three plant species of state significance were identified on the site juring the 1979 inventory. The Minnesota Natural Heritage Program lists Sea-Beach Triple-Awned Grass CAristida tuoerculosa), Rhombic Eveni~g Primrose (Oenothera rhombipetala), and Long-Bearded Hawkweed (Hieracium longipilum) as potential elements of state significance. The natural area is part of a small sand dune area within the Anoka Sandplain. Although this sandplain covers much of east central Minnesota, only portions of it have sand dune formationS(Cooper, 1938), and many of these have been disturbed by man. Many sand dunes of varying size are 1 An element is a natural feature of particular interest because it is exemplary, unique, threatened, or endangered on a national or statewide oasis. 4 found on Allison Savanna. Even though most dunes have been stabilized by vegetation, some active blowouts exist. A noteworthy successional plant community with characteristic sandbinding pioneer species is found in blowout areas. Allison Savanna supports serveral representative vegetation types, including oak savanna, dominated by Bur Oak and Northern Pin Oak (Quercus macrocarpa and Q. ellipsoidalis) in the overstory, sand blowouts with Sea-Beach Triple-Awned Grass and Hairy Panic Grass (Panicum lanuginosum, var. fasciculatum), and wet areas dominated by Hayden's Sedge (Carex haydenii). 5 ABIOTIC FACTORS The abiotic resources of an area provide a framework necessary to the existence of all life. The role of physical factors, involving processes of climate, geology, soils, and water is important in ecology. Biotic characters such as range, distribution, and diversity of plant and animal life are ultimately determined by potential limiting factors of the physical environment. These factors must be considered in any analysis of the biota of a natural area. The natural diversity of an area must be assessed in terms of abiotic as well as biotic elements. Unique physical characteristics, such as influential hydrologic conditions or landforms illustrating geologic processes contribute to overall diversity. The preservation value of a particular area may rest wholly on its abiotic features. The following sections describing climate, geology, soils and hydrology are an effort to describe the abiotic setting of Helen Allison Savanna. 6 CLIMATE Methods Climatological data were gathered by researching reports from the National Oceanic and Atmospheric Administration (NOAA), Minnesota. Agricultural Experiment Station, and Soil Conservation Service (SCS). MOst numerical data were obtained from the NOAA station at Cambridge, approximately 14 miles north of Helen Allison Savanna. Regional Climate The climate of east central Minnesota is typical of areas in the central part of the North American continent. Sharp seasonal contrasts in temperature and precipitation result from a lack of moderating factors, such as location near a large body of water. During summer months, southerly winds carry warm, moist -air masses northward from the Gulf of Mexico, making summer the season of greatest' precipitation. During winter, cold air masses invade from the north, making the winter months cold and dry. Discussion The mean temperature for June, July and August in the Helen Allison 0 Savanna area is 68 0 F; the December, January and February mean is 13 F. On the average, there are 14 days above 900 F. in the summer and about 45 days below '00 F. in the winter. The average duration of the freeze­ free season is 140 days. The length of the total crop season, which includes the growing period for both cool and warm season species, averages 210 days (Baker and Strub, 1963b). About 80%, or more than 21 inches, of the area's annual precipita­ tion (water equivalent) falls during the period of April through September. 7 Table 1. Sele'cted Weather Data for Cambridg.=-. TEMPERATURE of °c Mean annual temperature 42.0 5.6 Highest temperature recorded (14 July 1936) 109 42.8 Lowest temperature recorded (1 January 1935) -42 -41.1 Mean temperature warmest month Month: July Mean daily maximum 81.1 27.3 Mean daily minimum 59.0 15.0 Mean temperature coldest month Month: January 8.5 -13.1 Mean daily maximum 18.4 -7.6 Mean daily minimum -1.4 a -18.6 Average date last freeze (S pring6 c. 7 May 1 Average date first freeze (Fall) c . .l. Oct. c Average days freeze freeze seaaon 140 Average days total crop season ·210 PRECIPITATION in. cm. Mean annual precipitation 28.47 72.3 Mean precipitation wettest Month Month: June 4.77 12.1 Mean precipitation driest month Month: January 0.69 1.7 Mean annual snowfall 42.4 107.7 Mean snowfall heaviest month Month: December 9.3 23.6 aBased on Figure 3. Baker, D. G., and J. H. Strub, Jr. 1963a. Climate of Minnesota: Part I. Probability of Occurrence in Spring and Fall of Selected Low Temperatures. Minnesota Agr. Exp. Sta. Tech. Bull. 243. b Based on Figure 4. Baker and Strub, 1963a. cBased on Figure 16. Baker, D. G., and J. H. Strub, Jr. 1963b. Climate of Minnesota: Part II. The AgriCUltural and Minimum-Tempernture-rree Seasons. Minnesota Agr. Exp. Tech. Bull. 245. dBased on Figure 14. Baker, D~G., and J. H. Strub, Jr. 1963b. Climate of r~innesota: Part II. The Agricultural and Minimum-Temperature-Free Season Minnesota Agr. Exp. Sta. Tech. Bull. 245. 8 June is the wettest month, with numerous thunderstorms accounting for an average of 4.8 total inches of rain.